Corrosion resistance of welded high alloy austenitic stainless steels in sulphuric acid

TWI Industrial Member Report Summary 345/1987

By P I Marshall and T G Gooch

Background

While alloy element segregation in austenitic stainless steel weld metals is known to reduce pitting corrosion resistance in chloride environments, there is little information available on behaviour in other media such as inorganic acids. The present study has examined the sulphuric acid resistance of Type 904L wrought material, undiluted weld metals, and butt welds. Manual metal arc and TIG welds were produced, the former employing matching composition and more highly alloyed fillers. Potentiodynamic and potentiostatic test methods were employed using 30% sulphuric acid at room temperature, susceptibility to corrosion being correlated with microsegregation of alloying elements.